Notes

Overview

Chronic fatigue syndrome (CFS) is characterised by severe, disabling fatigue, and other symptoms, including musculoskeletal pain, sleep disturbance, impaired concentration, and headaches. Two widely used definitions of CFS, from the US Centers for Disease Control and Prevention (CDC; current criteria issued in 1994, which superseded the CDC criteria issued in 1988)[1] and from Oxford, UK,[2] were developed as operational criteria for research (see table 1). The principal difference between these definitions is the number and severity of symptoms, other than fatigue, that must be present. A third operational definition, the Australian criteria, is similar to the CDC diagnostic criteria, and has also been used in treatment trials.[3] The 1994 CDC criteria were reviewed with the aim of improving case ascertainment for research.[4] The exclusion criteria were clarified, and the use of specific instruments for the assessment of symptoms was recommended.[4]